Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 22	$ 23	$ 69	$ 69
Interest cost	53	55	160	164
Expected return on plan assets	(78)	(77)	(233)	(232)
Amortization of net actuarial loss	46	43	132	124
Amortization of prior service cost (credit)	1	0	1	0
Net periodic benefit cost (credit)	44	44	129	125
Pension Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	16	18	53	53
Interest cost	40	42	121	125
Expected return on plan assets	(56)	(55)	(167)	(165)
Amortization of net actuarial loss	32	31	94	88
Amortization of prior service cost (credit)	1	0	1	1
Net periodic benefit cost (credit)	33	36	102	102
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	7	7	20	20
Interest cost	18	20	55	60
Expected return on plan assets	(33)	(33)	(98)	(97)
Amortization of net actuarial loss	3	6	10	22
Amortization of prior service cost (credit)	(3)	(29)	(10)	(88)
Net periodic benefit cost (credit)	(8)	(29)	(23)	(83)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	5	5	15	15
Interest cost	14	15	42	46
Expected return on plan assets	(23)	(23)	(68)	(68)
Amortization of net actuarial loss	2	4	6	15
Amortization of prior service cost (credit)	(2)	(22)	(7)	(66)
Net periodic benefit cost (credit)	$ (4)	$ (21)	$ (12)	$ (58)